<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
</html>
<script>
    function f1() {
        var n = 99;
        function f2() {
            console.log(n);
        }
        return f2
    }
    // console.log(n);
    var res = f1();
    res()
</script>